Rotor shaft jack

ABSTRACT

An electric motor is provided. The motor includes a motor frame assembly including a motor frame and a motor housing. A stator is fixed relative to the motor frame assembly. A rotor including a rotor shaft is mounted in the motor frame assembly for rotational movement relative to the motor frame assembly about an axis. A rotor jack is operable to selectively support the rotor shaft. The rotor jack is shiftably coupled relative to the motor frame assembly for movement between a support position, in which the jack is shifted into supporting contact with the rotor shaft, and a retracted position, in which the jack is spaced from the rotor shaft.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority from U.S. Provisional PatentApplication Ser. No. 61/937,363, filed Feb. 7, 2014, and U.S.Provisional Patent Application Ser. No. 61/937,972, filed Feb. 10, 2014,the entire disclosures of each of which are hereby incorporated byreference herein.

The above-referenced provisional patent applications relate to and havethe same priority dates as corresponding ones of the followingprovisional patent applications: U.S. Provisional Patent ApplicationSer. No. 61/937,358, filed Feb. 7, 2014, and U.S. Provisional PatentApplication Ser. No. 61/937,968, filed Feb. 10, 2014, each entitledINTERNAL ROTOR SENSOR HAVING ADJUSTABLE SENSOR CARRIER; U.S. ProvisionalPatent Application Ser. No. 61/937,369, filed Feb. 7, 2014, and U.S.Provisional Patent Application Ser. No. 61/937,980, filed Feb. 10, 2014,each entitled TAPERED BEARING HOUSING AT COUPLED END OF CLOSE-COUPLEDMOTOR; U.S. Provisional Patent Application Ser. No. 61/937,297, filedFeb. 7, 2014, and U.S. Provisional Patent Application Ser. No.61/937,981, filed Feb. 10, 2014, each entitled STATOR CAGE FOR LARGEMOTOR; and U.S. Provisional Patent Application Ser. No. 61/937,366,filed Feb. 7, 2014, and U.S. Provisional Patent Application Ser. No.61/937,988, filed Feb. 10, 2014, each entitled ROTOR HAVING END BAFFLEFOR DIVERTING COOLANT. The entire disclosures of each of theabove-referenced related provisional applications are herebyincorporated by reference herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to electric motors. Morespecifically, the present invention concerns a motor assembly having arotor shaft jack.

2. Discussion of the Prior Art

Those of ordinary skill in the art will appreciate that motors are usedin a variety of applications, including, but not limited to, drivingcentrifugal pumps (such as slurry pumps). A motor regularly requiresmaintenance and repair, particularly with regards to the rotor bearings.The weight of motor components, especially in large centrifugal pumpapplications, are extremely heavy and can make bearing maintenancedifficult. When replacing a rotor bearing, it is desirable to minimizerotor deflection so as to prevent damage to the rotor and stator, aswell as facilitate the removal and installation of a new rotor bearing.

SUMMARY

According to one aspect of the present invention, an electric motor isprovided. The motor comprises a motor frame assembly including a motorframe and a motor housing, a rotor rotatable relative to the motor frameassembly about an axis, a stator fixed relative to the motor frameassembly, and a rotor jack. The rotor includes a rotor shaft rotatablysupported on the motor frame assembly. The rotor jack is operable toselectively support the rotor shaft. The rotor jack is shiftably coupledrelative to the motor frame assembly for movement between a supportposition, in which the jack is shifted into supporting contact with therotor shaft, and a retracted position, in which the jack is spaced fromthe rotor shaft.

This summary is provided to introduce a selection of concepts in asimplified form. These concepts are further described below in thedetailed description of the preferred embodiments. This summary is notintended to identify key features or essential features of the claimedsubject matter, nor is it intended to be used to limit the scope of theclaimed subject matter.

Various other aspects and advantages of the present invention will beapparent from the following detailed description of the preferredembodiments and the accompanying drawing figures.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

Preferred embodiments of the present invention are described in detailbelow with reference to the attached drawing figures, wherein:

FIG. 1 is a front perspective view of a motor assembly constructed inaccordance with a preferred embodiment of the present invention, whereinthe motor assembly is illustrated in a close-coupled relationship with alarge centrifugal pump;

FIG. 2 is a front perspective view of the motor assembly of FIG. 1, withthe pump being removed;

FIG. 3 is a rear perspective view of the motor assembly, as depicted inFIG. 2;

FIG. 4 is a front perspective view of the motor assembly of FIGS. 1-3,with the coolant gas system and side plates removed;

FIG. 5 is a side cross-sectional view of the motor assembly as depictedin FIG. 4;

FIG. 6 is an exploded front perspective view of the stator of theassembly of FIGS. 4-5, with the stator coils and windings removed;

FIG. 7 is a front perspective view of the stator of the assembly ofFIGS. 4-5;

FIG. 8 is an enlarged cross-sectional front view of the stator of FIG.7;

FIG. 9 is a front perspective view of the stator of FIGS. 4-5, and 7,within a fragmentary cross-sectional view of the motor frame assembly ofFIGS. 1-4;

FIG. 10 is an exploded front perspective view of the rotor of theassembly of FIGS. 1-2 and 4-5.

FIG. 11 is a front perspective view of the rotor of FIG. 10;

FIG. 12 is an enlarged rear perspective view of the rotor and statorFIGS. 4-5, with the flow of coolant gas illustrated;

FIG. 13 is a fragmented bottom, rear perspective view of the motorassembly of FIG. 4, with one motor chamber access plate removed;

FIG. 14 is an enlarged, partially sectioned rear perspective view of themotor frame assembly, closed end bearing assembly, rotor shaft jack, androtor sensor mechanism of the assembly of FIGS. 1-5 and 13;

FIG. 15 is an enlarged, partially sectioned side view of the motor frameassembly, closed end bearing assembly, rotor shaft jack, and rotorsensor mechanism of FIG. 14;

FIG. 16 is an enlarged, fragmented and partially sectioned view of therotor and rotor shaft jack taken along line 16-16 of FIG. 15,particularly illustrating the jack in the retracted position;

FIG. 17 is an enlarged, fragmented, and partially sectioned view of therotor and rotor shaft jack similar to FIG. 16, but depicting the jack inthe supporting configuration;

FIG. 18 is an enlarged, fragmented, partially sectioned, and explodedfront perspective view of the rotor, bearing, and rotor shaft jack ofFIGS. 13-17, depicting the jack in the supporting configuration and thebearing removed from the rotor shaft;

FIG. 19 is an enlarged, fragmented, and partially sectioned side view ofthe motor frame assembly, shaft ring, and rotor of the assembly of FIGS.1-5, with the shaft ring in a supporting relationship with the rotor;

FIG. 20 is an enlarged, fragmented, partially sectioned, and explodedfront perspective view of the motor frame assembly, rotor, bearingspacer, and inner bearing cap of the assembly of FIGS. 1-5, with therotor axis deflection illustrated;

FIG. 21 is a front perspective view similar to FIG. 20, but depictingthe bearing spacer, inner bearing cap, and a bearing in an installedconfiguration;

FIG. 22 is a partially sectioned front perspective view of FIGS. 20-21,with alignment studs inserted in the inner bearing cap, and the bearinghousing of the assembly of FIGS. 1-5;

FIG. 23 is a partially sectioned front perspective view similar to FIG.22, particularly illustrating the bearing housing engaging the motorframe assembly;

FIG. 24 is an enlarged, fragmented, and partially sectioned side view ofthe structure depicted in FIG. 23;

FIG. 25 is a view similar to FIG. 24, but depicting the bearing assemblyin an installed configuration, and the shaft ring in an unsupportingrelationship with the rotor.

FIG. 26 is a partially sectioned front perspective view of the drive endof the motor assembly, depicting the bearing access plate removed;

FIG. 27 is an enlarged, fragmented front perspective view of the closedend of the motor assembly, with another motor chamber access plateremoved, also showing the sensor processor and sensor mechanism;

FIG. 28 is an exploded, fragmented, exploded front perspective view ofthe closed end bracket, sensor mechanism, bearing assembly, and rotor;

FIG. 29 is an enlarged, rear perspective view of the closed end bracketand sensor mechanism of FIG. 28;

FIG. 30 is a top perspective view of the sensor carrier and sensors ofFIGS. 27-29;

FIG. 31 is a bottom perspective view of the sensor carrier and sensorsof FIGS. 27-30;

FIG. 32 is a top fragmentary view of the structure depicted in FIGS.27-29;

FIG. 33 is a cross-sectional view taken along line 33-33 of FIG. 32; and

FIG. 34 is a cross-sectional view taken along line 34-34 of FIG. 33.

The drawing figures do not limit the present invention to the specificembodiments disclosed and described herein. The drawings are notnecessarily to scale, emphasis instead being placed upon clearlyillustrating the principles of the preferred embodiments.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is susceptible of embodiment in many differentforms. While the drawings illustrate, and the specification describes,certain preferred embodiments of the invention, it is to be understoodthat such disclosure is by way of example only. There is no intent tolimit the principles of the present invention to the particulardisclosed embodiments.

With initial reference to FIG. 1, a pump-motor assembly 40 constructedin accordance with the principles of an embodiment of the presentinvention is depicted for use in various applications. The illustratedpump-motor assembly comprises a switched-reluctance motor assembly 42closely coupled to a centrifugal pump 44 and is configured to providedriving power thereto, as will be readily understood by one of ordinaryskill in the art. The motor assembly 42 presents a plurality of mountingholes 46 for receiving fasteners (not shown) secured to a centrifugalpump 44, although various connecting structures (also not shown) may bealternatively used without departing from the teachings of the presentinvention.

While the pump-motor assembly 40 is useful in various applications, theillustrated embodiment has particular utility when the motor assembly 40is configured to provide driving power to a centrifugal pump 44, such asa slurry pump, and is used as a centrifugal slurry pump motor. Suchslurry pumps are used in various applications, but the illustratedembodiment is particularly suited for use in mining operations, such astransporting mined material and liquid as desired. The structure andoperation of the centrifugal pump 44 may be generally conventional innature and need not be described in further detail here.

Referring to the drawings, first to FIGS. 2 and 3, the motor assembly 42presents a drive end 48 and a closed end 50. The motor assembly 42broadly includes a motor frame assembly 52 having a motor frame 54 and amotor housing 56. The motor assembly 42 also includes a main powercomponent 58 for providing electrical power to at least some parts ofthe motor assembly 42, and a coolant gas system 60 for cooling at leastsome parts of the motor assembly 42 as described in more detail below.

The motor housing 56 is generally in a fixed relationship with the motorframe 54. In a preferred embodiment, the motor frame 54 and motorhousing 56 are comprised of steel and are removably fixed to one anotherto form a single motor frame assembly 52. As illustrated in FIGS. 4 and5, the motor frame assembly 52 substantially houses a stator 62 and arotor 64, the stator 62 is fixed to the motor frame 54, and the rotor 64is securely coupled to the motor frame assembly 52 for rotation relativeto the stator 62. The motor frame assembly 52 further presents aninternal motor chamber 66 for facilitating coolant gas circulationproduced by the coolant gas system 60. The motor frame assembly 52broadly includes a closed end plate assembly 68, a drive end plateassembly 70, interconnecting bars 72, and side plates 74.

The closed end plate assembly 68 includes an end plate 76, a closed endbracket 78, motor chamber access plates 80, and a bearing cover assembly82. The motor chamber access plates 80 are removably attached (withfasteners 84) to the closed end bracket 78 that, when removed, presentsa window 192 (described further below) that provides access to the rotorshaft 86 adjacent the closed end 50 of the motor assembly 42. Thebearing cover assembly 82 includes a bearing access plate 88 and an endcap 90. The bearing access plate 88 is removably fixed to the closed endbracket 78 with at least one fastener 92, and the end cap 90 isremovably fixed to the bearing access plate with at least one fastener94. Removal of the bearing cover assembly 82 exposes the first bearing96 and the bearing support surface 98 that securely houses the firstbearing 96. The drive end plate assembly 70 includes an end plate 100, abearing housing 102, and a bearing cover plate 104, as described in moredetail below.

Turning now to FIG. 5, the motor assembly 42 broadly includes a rotor 64and a stator 62 spaced radially from the rotor 64. The stator 62 issecured to the motor frame assembly 52 in a manner that limits rotationof the stator 62 relative to the motor frame assembly 52. The rotor 64is rotatably coupled to the motor frame assembly 52, such that the rotor64 can rotate relative to the stator 62 (and the motor frame assembly52) on a central rotational axis 106. The rotor 64 and the stator 62 areboth contained within the motor chamber 66 defined by the motor frameassembly 52. The motor frame assembly 52 at least substantially housesthe rotor 64 and the stator 62. A rotor drive shaft 110 projects axiallyoutwardly relative to the drive end 48 of the motor assembly 42 tosuitably provide driving power to the centrifugal pump 44, as will bereadily understood by one of ordinary skill in the art upon review ofthis disclosure.

The motor assembly 42 has an electromagnetic drive system operable todrive rotation of the rotor. Generally, the electromagnetic drive system112 includes a plurality of magnets and/or electromagnets 114 on or inthe rotor 64 and stator 62 and arranged so electromagnetic forces can beproduced by the drive system 112 to drive rotation of the rotor 64relative to the stator 62. In the illustrated embodiments, the stator 62utilizes large stator coils or windings 116 to generate electromagneticfields. Various electromagnetic drive systems can be used within thescope of the invention. Electromagnetic drive systems are well-known inthe art and will not be discussed in further detail herein.

Stator

The motor assembly 42 of this embodiment is generally made in relativelylarge sizes, e.g., from about 40,000 lb. to 50,000 lb. in weight, andsuitable for use with slurry pumps. In this embodiment, the motorassembly 42 may include a stator core weighing in the range of about10,000 lb to 15,000 lb. The need to operate a motor in slurry pumpapplications requires motor components that are adapted to handlerelatively high torquing forces. As such, the motor assembly of thisembodiment may be rated at about 1.5 MW at 400 RPM.

In the illustrated embodiment, the stator 62 generally includes a statorcore 118, a plurality of coils or windings 116 supported in the statorcore 118, and a stator cage 120. The stator core 118 preferably includesa stack of laminations 122, although a monolithically formed stator coreis permissible according to some aspects of the present invention. Acentral opening 124 preferably extends through the laminations 122. Thestator core 118 thus preferably presents both inner and outer radialcore margins. The central opening 124 preferably receives the rotor 64,such that the motor is an inner rotor motor. It is permissible accordingto some aspects of the present invention, however, for the motor to bean outer rotor motor. The central opening 124 is preferably concentricwith the laminations 122. Turning now to FIGS. 6 and 7, the stator core118 of this embodiment is generally cylindrical as shown, so as to havea stator core outer diameter, though other shapes are contemplated.Elements of the stator core 118 may be made of any ferromagneticmaterial, including powdered metal, among other possible materials. Thelaminations provide a plurality of circumferentially spaced apart polesegments 126 preferably projecting inwardly (in keeping with thepreferred inner rotor embodiment) into the central opening 124. In theillustrated embodiments, the laminations 122 provide a series ofcorresponding recessed areas 128 for receiving bars 130 that are inradial alignment with the stator core pole segments 126.

The stator coils or windings 116 present end turns 132 at opposite axialends of the stator core 118. The stator coils or windings 116 aresecured to the lamination stack 122 through a series of stator coil orwinding retention devices 134. The stator presents a plurality ofcircumferentially spaced slots 135 extending along the axial lengththereof, each of which is defined between an adjacent pair of polesegments 126. The stator coils 116 are wrapped around the pole segmentsso as to be generally located within the slots 135. Various techniquesand devices that are well known in the art can be used to arrange andmount the stator coils or windings 116 to the stator core 118. Thus,these techniques and devices will not be described in any furtherdetail.

Because the stator 62 is intended for use in large motor applications,the stator cage 120 is provided to securely interconnect the laminations122 and to provide structure to facilitate lifting and manipulation ofthe stator 62. The stator cage 120 preferably includes a plurality ofbars 130 that extend generally axially along the outer surface of thelaminations 122. The bars 130 preferably present axial bores 136 on atleast one end thereof and, more preferably, bores at each of the ends.Preferably, at least some of the bores 136 are threaded to receive athreaded fastener, as will be explained. The bars 130 are received inthe recessed areas 128, eliminating the likelihood of relative rotationbetween the stator core 118 and stator cage 120.

Stator end plates 138 are preferably but not necessarily of a generallytoroidal shape so as to present end plate outer diameters. The statorend plates 138 are preferably concentrically disposed at the oppositeends of the stack of laminations 122. The stator end plates 138 presenta plurality of circumferentially spaced openings 140 near the outeredge, with some of the openings 140 corresponding to the axial bores 136of the stator cage bars 130.

Preferably, a portion 138 a of each stator end plate 138 extendsradially beyond the outer radial core margin. Most preferably, asillustrated, such portion 138 a extends at least substantiallycontinuously circumferentially so as to be generally annular in form.(Thus, in a preferred embodiment, the end plates 138 have a largerdiameter than the stator core 118). The openings 140 are preferablydefined by the respective end plate portions, such that the openings arepositioned radially beyond the outer radial core margin. It isparticularly noted that, although extension and positioning beyond theouter radial core margin is preferred, additional or alternativeextension and/or positioning beyond the inner radial core margin is alsopermissible according to some aspects of the present invention.

As noted previously, in a preferred embodiment, the stator core 118 and,in turn, the outer radial core margin, is preferably generallycylindrical (i.e., generally circular in cross-sectional shape).Similarly, the end plates 138 are preferably generally toroidal, withthe end plate portions 138 a thus being generally circularly annular. Itis reiterated, however, that non-circular/cylindrical/annular forms arepermissible as well. Preferably, regardless of shape, a portion of eachof the end plates extends beyond the outer core margin. That is, innon-circular/cylindrical/annular embodiments, the corresponding outerdimensions of the stator core and the end plates are of importance. Forinstance, the end plate might be in the form of a square having agreater side dimension than the diameter of a cylindrical core, so as topresent a continuously extending outer end plate portion, or the endplate and the core might both have equal-sized octagonal cross-sectionsbut be rotated relative to each other such that eight (8) discretecorners of the end plate project past respective ones of the eight (8)straight sides of the core. It is noted that such non-circular outerperimeters are particularly feasible in conjunction with the preferredinner rotor design.

The ends of the bars 130 each preferably abut respective ones of thestator end plates 138. Preferably, the stator end plates 138 and bars130 are fixedly secured to one another. In this embodiment, the bars 130are skip welded on each side to the laminations 122 and also welded atthe ends to each end plate 138. Various techniques may be suitable forfixedly securing the stator cage 120 components to one another whilestaying within the scope of the invention.

Preferably, each stator end plate 138 presents a radially outermost endplate margin. Furthermore, each bar 130 preferably presents a generallyaxially extending radially outermost bar margin. As shown in FIG. 8 andothers, the radially outermost end plate margins are each preferablyspaced radially outside the radially outermost bar margins. That is, apart 138 b of each end plate portion 138 a preferably extends radiallybeyond the outer radial bar margins.

As illustrated, the end plates 138 present a series of teeth 142 thatpreferably project radially inward (in keeping with the preferred innerrotor embodiment) and overlay the axial ends of the lamination poles126, providing extra security to the laminations 122 and furtherpreventing lamination flaring. The teeth 142 are forked to assist withheat dissipation associated with the lamination pole segments 126,although the teeth 142 may present various configurations withoutdeparting from the scope of the present invention.

Preferably, at least some of the circumferentially spaced openings 140in the stator cage end plates 138 can be used to facilitate lifting ofthe stator 62. However, it is within the scope of the invention toconsider other potential uses for the openings 140. For example, some ofthe circumferentially spaced openings 140 in the stator cage end plates138 in alignment with the stator cage bars 130 can provide mountingpoints for various motor components. The aligned bores 136 and openings140 may alternatively be used to facilitate lifting and manipulation ofthe stator. Yet further, any openings 140 in the end plates 138 notaligned with a corresponding bore 136 may also be used to facilitatelifting and manipulation of the stator. If the exposed bore is threaded,a threaded lifting clevis (or other suitable connector) can be coupledto the bore 136.

In the illustrated embodiment, a series of buss rings 144 are arrangedin axial alignment relative to one end of the stator core 118.Preferably, the buss rings 144 are fixedly coupled to one another with aplurality of circumferentially spaced insulated brackets 146. Eachbracket 146 preferably presents an opening (not shown) that receives afastener 148. The fastener 148 extends through the buss ring bracket146, through a respective one of the openings 140 of the stator cage endplate 138, and secures into the axial bore 136 of the corresponding bar130, fixedly coupling the buss rings 144 to the stator cage 120. Eachbuss ring 144 includes a tab 150 that serves as a power lead for pullinga current from wires (not shown) connected to the main power component58, in turn, providing power using wires (not shown) directed to thestator coils or windings 116. In a preferred embodiment, the buss rings144 and tabs 150 are comprised of a conductive material, such as copper.

Turning now to FIG. 7, the fully assembled stator 62 includes the statorcore 118, stator cage 120, stator coils or windings 116, and buss rings144. Although the illustrated embodiment includes buss rings 144, otherforms of power leads to the stator coils or windings 116 may beconsidered without departing from the teachings of the presentinvention.

Referring now to FIG. 8, once again illustrating the stator cage 120 inan assembled state, the outer circumference of the stator cage endplates 138 are slightly larger than the outer circumference defined bythe stator cage bars 130. The outer circumference defined by the statorcage end plates 138 provide for fit placement of the stator 62 into themotor frame 54, as illustrated in FIG. 9. The motor frame 54 includes acircumferential support surface 152 for receiving the stator 62 andsupporting the stator 62 by engaging the stator cage end plates 138.Preferably, the stator cage 120 is fixedly secured to the motor frame54. Various techniques and structures well-known in the art are suitablefor fixedly securing the stator cage 120 to the motor frame 54. Thus,securing the stator cage 120 to the motor frame 54 will not be discussedin any further detail herein.

Coolant Gas Diverter Plate

Referring back to FIGS. 2 and 3, as is somewhat conventional and readilyappreciated by one of ordinary skill in the art, the motor assembly 42includes a coolant gas system 60 preferably having a heat exchanger. Inthe illustrated embodiment, the coolant gas system 60 includes anexternal coolant (preferably gas) circuit, wherein external coolant gasis drawn through an external coolant gas intake 154, passed through theheat exchanger, and released through a coolant gas exhaust 156. Thecoolant gas system 60 also includes a closed internal coolant gascircuit, wherein internal coolant gas is circulated between the motorchamber 66 and the heat exchanger, such that heat from the internalcoolant gas is absorbed by the external coolant gas, and released. Thestructure and operation of the heat exchanger may be generallyconventional in nature and need not be described in further detail here.Furthermore, if desired, the gas coolant system 60 may be alternativelyconfigured without departing from the spirit of the invention. Forexample, the heat exchanger may be eliminated altogether, such that thecoolant (e.g., ambient air) is passed directly through the motorchamber.

It is known that electric motors often generate a significant amount ofheat that must be dissipated. The coolant gas system 60 is operable toproduce a fluid flow of coolant gas through the rotor 64 and stator 62from a first end to a second end, and return coolant gas to the heatexchanger for heat dissipation and recirculation. In the illustratedembodiment, the coolant gas is circulated between the closed end 50 ofthe motor chamber 66, to the drive end 48 of the motor chamber 66, tothe heat exchanger, then recirculated. Preferably, the coolant gassystem 60 is an air-to-air exchanger, though other heat exchangers andcoolant systems are within the scope of the present invention.

With brief reference back to FIG. 5, the rotor 64 includes a rotor core158 having a central shaft opening 160 extending through the laminations162 and end plates 164, and receiving a rotor shaft 86 with a first andsecond bearing 96,166 mounted thereon. The rotor shaft 86 is rotatablycoupled to the motor frame assembly 52. As in the illustratedembodiment, the rotor shaft 86 is supported on each end with thebearings 96,166 securely coupled to the motor frame assembly 52. Therotor 64 is coupled in a manner that allows the rotor 64 to rotaterelative to the stator 62 on a central rotational axis.

Turning now to FIG. 10, the rotor core 158 includes a stack oflaminations 162. End plates 164 are concentrically disposed at oppositeends of the stack of laminations 162. A central shaft opening 160extends through the laminations 162 and end plates 164, and receives therotor shaft 86. The central shaft opening 160 is concentric with thelaminations 162. The rotor core 158 of this embodiment is generallycylindrical as shown, though other shapes are contemplated. Elements ofthe rotor core 158 may be made of any ferromagnetic material, includingpowdered metal, among other possible materials. The rotor core 158 maybe made of stacked individual stampings or laminations.

The laminations 162 include a plurality of coaxial fastener holesextending therethrough (not shown). Each of the lamination holesreceives one of a plurality of stainless steel pins 168. A head 170 ofeach pin 168 contacts one of the end plates 164, and the end plates 164may include counterbores 172 as shown to receive each head 170. Each pin168 extends all the way through the rotor core 158 and protrudes fromthe other end of the plates 164. Each pin 168 of this embodiment hasspaced-apart, circumferential grooves near its end (not shown). Theportion of the pin 168 protruding from the plate 164 has the groovesthereon. One of the plurality of stainless steel collars 174 is receivedover and engages one of the pins 168, the pin 168 and collar 174 being alocking fastener set of this embodiment. The collar 174 also contactsthe end plate 164. As will be appreciated by one of ordinary skill inthe art, the end plates 164 can use various methods of attaching to therotor core 158 that are within the scope of the invention.

The rotor core 158 is designed to allow coolant gas to flow from theclosed end 50 of the motor chamber 66 to the drive end 48 thereof. Moreparticularly, the outer diameter of the core 158 includes a plurality ofaxially extending coolant gas passages 176 alternately arranged with aplurality of circumferentially spaced apart pole segments 178. Thecoolant gas passages 176 extend axially along the circumference of therotor 64. In the illustrated embodiment, each of the coolant gaspassages 176 is spaced equally about the same distances from the rotoraxis 180. Each coolant gas passage 176 is a separate coolant gas passage176 and is substantially parallel to the rotor axis 180. In a preferredembodiment, each pole segment edge 182 maintains a substantiallyorthogonal relationship to its adjacent coolant gas passage 176,respectively. However, pole segments 178 and coolant gas passages 176 ofvarying constructions and arrangements are within the scope of thepresent invention.

When the coolant gas is circulated by the coolant gas system 60, coolantgas is at least directed through the closed end 50 of the motor chamber66, directed through the motor chamber 66 between the stator 62 and therotor 64, and dispersed outwardly relative to the drive end 48 of themotor chamber 66. In the illustrated embodiment, a coolant gas diverterplate 184 is mounted coaxially to the rotor 64 so that the rotor axis180 coincides with the axis of the diverter plate 184. The diverterplate 184 is positioned axially between the drive end 48 of the rotorcore 158 and the end plate 164. The diverter plate 184 is suitablysecured to the rotor core 158 and end plate 164 so that they all rotateas a singular body, as illustrated in FIG. 11. The diverter plate 184presents a diameter that is at least greater than the core diameterdefined by the coolant gas passages 176. In the illustrated embodiment,the diverter plate 184 diameter is substantially equal to the core 158diameter presented by the pole segments 178.

The diverter plate 184 is preferably a disc that is circular in shape.However, the diverter plate 184 could alternatively be segmented ratherthan one continuous disc. Moreover, a diverter plate 184 configured indifferent shapes is also within the ambit of certain aspects of thepresent invention. In the illustrated embodiment, the diverter plate 184is positioned at the downstream end 186 (relative to the flow directionof the coolant gas) of the coolant gas passages 176. Therefore, in thepreferred embodiment, the plate 184 redirects coolant gas radiallyoutward toward the stator 62. The diverter plate 184 functions as abaffle or dam that forces coolant gas to disperse towards and dissipateheat from at least some stator pole segments 126, stator coils orwindings 116 adjacent the stator slots 135, and end turns 132 of thestator coils or windings 116. It is also further noted that each passage176 is open and unobstructed upstream 188 from the diverter plate 184.This preferred configuration facilitates coolant flow through the rotor64 until it is desired to direct it radially outward toward the stator62.

Referring now to FIG. 12, the diverter plate 184 is positioned to divertthe flow of coolant gas 186 from the coolant gas passages 176 toward thestator 62. The coolant gas 186 is forced into the motor chamber 66 byfluid flow created by the coolant gas system 60. The coolant gas 186enters the coolant gas passages 176 of the rotor core 158 adjacent theclosed end 50 of the motor chamber 66. The coolant gas 186 passessubstantially parallel along the coolant gas passage 176 from theupstream end of the rotor core 188 to the downstream end of the rotorcore 186. The path of the coolant gas 186 flow is then diverted by thediverter plate 184, redirecting coolant gas 186 flow radially outwardrelative to the rotor axis 180 to cool the stator 62.

Again, as previously noted, the principles of the present invention areapplicable to alternative diverter plate designs. For example, thediverter plate 184 can comprise one or more plates of variousconstructions while staying within the scope of the invention. Thediverter plate 184 can be in various shapes to conform with differentrotor shapes. The diverter plate 184 can also be constructed with avariable diameter and radial projection angles, so as to provide variousdiverted flow angles from each coolant gas passage 176. The diverterplate 184 may also be alternatively designed so as not to be associatedwith each and every passage 176, as shown. The diverter plate 184 couldalso be designed for use with other coolants (e.g., a liquid coolant).

Rotor Shaft Jack

As will be readily appreciated by one of ordinary skill in the art,operation of a motor, particularly under a load, can lead to a prematurebreakdown of lubricants (e.g., in the bearings). Periodical maintenancemay require cleaning or even the replacement of bearings to preventinterference with desired operation of the motor. As best illustrated inFIG. 5, the axial ends of the rotor shaft 86 are rotatably supported onbearings 96,166 securely coupled to the closed end 50 and the drive end48 of the motor frame assembly 52. In the illustrated embodiment, therotor 64 can weigh in the range of about 10,000 lb to 15,000 lb. As canbe appreciated by one of ordinary skill in the art, the removal andreplacement of a bearing that supports a rotor of this weight,necessitates a means to avoid substantial deflection of the rotor from acentral rotational axis. The minimization of rotor deflection, in turn,facilitates reassembly after maintenance has been completed.

As shown in FIG. 13, removal of a motor chamber access plate 80 presentsa window 192 to a rotor shaft jack 194. The rotor jack 194 is shiftablycoupled relative to the motor frame assembly 52 for movement between arotor-supporting position and a retracted, non-supporting position. Ascan be appreciated by one of ordinary skill in the art, a rotor shaftjacking mechanism would not need to support the rotor 64 when the rotor64 is supported by the closed end bracket 78, and thus the motor frameassembly 52. As illustrated in FIGS. 14 and 15, the jacking component196 is in a retracted position while the bearing access plate 88 issecurely attached to the closed end bracket 78. In the illustratedembodiment, the bearing 96 is securely housed within the bearing supportsurface 98, thereby supporting the rotor 64. The jacking component 196preferably includes a threaded shaft 198 (e.g., a bolt) threadablyengaging the closed end bracket 78, such that rotation of the shaft 198causes axial shifting of the respective jacking component 196 betweenthe supporting and retracted positions. Preferably, an operator accessesthe jacking component 196 through the window 192 after the access plate80 is removed, to manually screw the jacking component 196 between thesupporting and retracted positions. However, the principles of thepresent invention are equally applicable to alternative jackingcomponents 196 that are shifted between the supporting and retractedpositions. For example, the jacking components 196 could be hydrauliccylinders, pneumatic pistons, or electronic solenoids. Further, althoughillustrated, the jacking component 196 is manually rotated to causeshifting of the jacking component 196 relative to the closed end bracket78. However, the jacking component 196 could alternatively be powered(e.g., with an electric motor) while staying within the scope of someaspects of the invention.

Turning now to FIGS. 16 and 17, each of the jacking components 196 has atip 200 made of a low-friction material, preferably nylon. Thelow-friction tips 200 inhibit corrosion and adherence between thejacking components 196 and the rotor shaft 86. Although the low-frictiontips 200 are a preferred component of the jacking components 196, it isnoted that the jacking components 196 can function without thelow-friction tips 200. However, other means of protecting the rotorshaft 86 may be used without departing from the scope of the invention.

With continued reference to FIG. 16, the illustrated embodiment includesa pair of threaded jacking components 196 that project radially relativeto the rotor shaft 86. The jacking components 196 are angularly spacedat an angle from about thirty degrees to ninety degrees, with apreferred angle of about forty degrees. With attention now specificallyto FIG. 17, the illustrated embodiment demonstrates the rotor jack 194in a supporting position with the rotor shaft 86.

With attention now to FIG. 18, the rotor jack 194 is shifted into thesupporting position such that the weight and position of the rotor 64,previously supported by the bearing 96, is subsequently shifted over tothe rotor jack 194. Preferably, the rotor shaft 86 is stopped prior toshifting the rotor jack 194 into the supporting position. After therotor jack 194 is in supporting contact with the rotor shaft 86, thebearing cover assembly 82 can be removed. In more detail, once the rotorjack 194 is in supporting contact, the bearing access plate 88 can beremoved from the closed end bracket 78. If the rotor jack 194 support issufficient enough to lift the relative rotor weight off of the bearing96, the bearing 96 is easily removed. Once the bearing 96 is removedfrom the rotor shaft 86, the bearing 96 may be serviced or replaced, andsubsequently reinstalled. Upon reinstallation, the jack 194 can beretracted from supporting contact with the rotor shaft 86 so that thenew or serviced bearing 96 is now supporting the weight and position ofthe rotor shaft 86.

If desired, prior to removing the bearing 96, any suitable indicator maybe used to actively or passively signal to an operator that the shaft is86 supported for safe removal or servicing of the bearing. This willavoid excessive shaft deflection and signal to the operator that therotor shaft 86 has been slightly lifted within the bearing tolerances.For example, a dial indicator (not shown) may be placed on the rotorshaft 86 to show when the shaft has moved into a supported condition.Once the indicator signals that the shaft 86 is supported, the bearing96 may be removed or otherwise serviced. In another embodiment, anoptical sensor (not shown) may be coupled to the motor frame assembly 52to sense when the rotor shaft 86 has been lifted. Once the opticalsensor signals that the shaft 86 is supported, the bearing 96 may beremoved and serviced. In an another embodiment, a deflection limiter(not shown) may be fixed to the motor frame assembly 52. For example,the limiter may be positioned above and in close proximity to the rotorshaft 86, such that lifting of the rotor shaft 86 is limited to a heightdefined by the limiter. As such, once vertical movement of the rotorshaft 86 is stopped by the limiter, further rotation of the jackingcomponents 196 is resisted, indicating to the operator that the shaft 86is supported, such that the bearing 96 may be removed and serviced.

Tapered Bearing Housing

Turning now to the drive end 48 of the motor assembly 42 shown in theillustrated embodiment of FIG. 5, the drive end 48 of the rotor shaft 86is rotatably supported by the second bearing 166. The bearing 166 issecured within a bearing housing 102, both of which form part of abearing assembly 202. The bearing housing 102 is interposed between thebearing 166 and motor frame assembly 52. The bearing 166 issubstantially housed within the bearing housing 102, and the bearinghousing 102 is releasably attached to the motor frame assembly 52 so asto be selectively secured in supporting relationship with the bearing166 and thereby the rotor 64.

The motor frame assembly 52 presents a circumferentially extendingsupport face 204 that extends coaxially from the central rotational axis106. The bearing housing 102 presents an engagement face 206 thatengages the support face 204 of the motor frame assembly 52. In theillustrated embodiment, the engagement face 206 faces radially outwardand the support face 204 faces radially inward. However, thisorientation may be reversed without departing from the spirit of thepresent invention.

The motor frame assembly 52 of the illustrated embodiment also includesa central housing bore 208 in which the bearing housing 102 is received,though the invention is not limited to the presence of a central housingbore 208 (particularly if the orientation of the engagement and supportfaces is reversed). The central housing bore 208 of the illustratedembodiment includes a shaft ring 210 that circumscribes the rotor shaft86 in close proximity, though the shaft ring 210 being rigidly attachedto the motor frame assembly 52 without a central housing bore 208 hasalso been contemplated. When the bearing housing 102 is in a supportingrelationship with the rotor shaft 86, the shaft ring 210 is in a coaxialrelationship with the rotor shaft 86, such that the rotor shaft 86 canrotate freely within the shaft ring 210.

The shaft ring 210 has a support face 212 that engages the rotor shaft86 when the bearing housing 102 is out of the supporting relationship.As illustrated in FIG. 19, the shaft ring 210 is in a supportingrelationship with the rotor shaft 86 when the bearing housing 102 is notin such a supporting relationship. Consequently, the relative weight ofthe rotor 64 is supported by the motor frame assembly 52. As furtherillustrated in FIG. 20, the shaft ring 210 is in close proximity to thecircumference of the rotor shaft 86, such that once the bearing housingassembly 202 is taken out of supporting relationship, the shaft ring 210minimizes the deflection of the rotor axis 180 from its centralrotational axis 106. Preferably, the radial gap between the shaft ring210 and the rotor shaft 86 is less than one-tenth ( 1/10) and, morepreferably, one-one hundredth ( 1/100) the rotor shaft diameter at theaxial location of the ring 210. This is particularly desirable in largemotor applications where the significant rotor weight could cause motordamage if one end of the rotor 64 is left unsupported.

In the illustrated embodiment, the rotor shaft 86 has a rotor shoulder214 and a drive shaft 110. The rotor shoulder 214 presents a shoulderdiameter that is greater than the drive shaft diameter. The drive shaft110 is designed to project axially from the motor frame assembly 52 fordriving connection with the pump 44. The bearing assembly 202 includes atoroidal bearing spacer 216 that is slidably fit onto the rotor driveshaft 110 adjacent the rotor shoulder 214 to provide a support surface218 for the inner bearing cap 220. The bearing spacer 216 also presentsa spacer inner diameter substantially equal to the drive shaft diameter,as well as a spacer outer diameter that is less than the rotor shoulderdiameter. The bearing spacer 216 has an inner bearing engagement face222 along the outer axial end of the spacer 216, such that the bearingengagement face 222 engages with the inner race of the bearing 224. Thebearing assembly 202 also includes an inner bearing cap 220 that isslidably fit onto the outer diameter of the bearing spacer 216. Theinner bearing cap 220 presents a bearing cap inner diametersubstantially equal to the bearing spacer outer diameter, and less thanthe rotor shoulder diameter, such that the bearing cap 220 cannot slidebeyond the axial edge of the rotor shoulder 214. The inner bearing cap220 also has an outer bearing engagement face 226 along an axial end ofthe cap 220, such that the outer bearing engagement face 226inter-engages with the outer race 228 of the bearing 166. Turning now toFIG. 21, the bearing inner race 224 is flush against the bearing spacer216 and the bearing outer race 228 is flush against the inner bearingcap 220. As will be readily appreciated by one of ordinary skill in theart, the bearing spacer 216 and inner bearing cap 220 may be optional invarious motor assembly configurations, or of different construction andconfiguration without departing from the scope of some aspects of theinvention.

As shown in FIGS. 20 and 21, the drive end 48 of the motor frameassembly 52 includes a plurality of fastener-receiving openings 230 forsecurement of the bearing housing 102 to the motor housing 56, and thusthe motor frame assembly 52. The inner bearing cap 220 also presents oneor more fastener-receiving openings 232 for securement to the bearinghousing 102. Turning to FIG. 22, the bearing housing 102 includes aplurality of circumferentially spaced fastener-receiving holes 234, eachfor receiving a respective fastener 236 (e.g., a bolt) that is alsoreceived within the corresponding hole 230 of the motor housing 56. Thebearing housing 102 also includes one or more fastener-receiving holes238, each receiving a fastener 240 (e.g., a socket head cap screw) thatis also received within the corresponding hole 232 of the inner bearingcap 220.

In the illustrated embodiment, alignment studs 242 are temporarilyplaced into respective ones of the fastener-receiving openings 232 ofthe inner bearing cap 220. The alignment studs 242 provide assistance inmaintaining axial alignment between the fastener-receiving holes 238 ofthe bearing housing to the corresponding holes 232 of the inner bearingend cap. The bearing housing 102 is slidably placed over the rotor shaft86 and alignment studs 242, moving axially inwardly relative to the endof the rotor drive shaft 110, when the bearing housing 102 is shiftedinto a supporting relationship relative to the bearing 166. As bestillustrated in FIGS. 23 and 24, as the bearing housing 102 moves axiallyinward relative to the drive shaft 110 end, the bearing housingengagement face 206 engages the motor housing support face 204.

In the illustrated embodiments, the bearing housing 102 includes anengagement face 206 that presents a straight section 244 ofsubstantially constant diameter, as well as a tapered section 246 havinga variable diameter that progressively increases toward the straightsection and stops increasing at the straight section. The taperedsection 246 is located at the axially inner end of the housing 102 sothat the wider portion of the engagement face 206 engages the supportface 204 first. The support face 204 of the motor frame assembly 52preferably has a constant diameter. However, it is understood that thesupport face 204 of the motor frame assembly 52 can alternatively betapered in part without departing from the spirit of the presentinvention. It is further appreciated that the motor housing support face204 can include a tapered section in addition to, or in lieu of, thebearing housing 102 including a tapered section 246. In the illustratedembodiment, the bearing housing 102 presents the tapered section 246 tofacilitate smooth transition of the bearing housing 102 fromanon-supporting relationship into a supporting relationship.

Turning to FIG. 24, the illustrated embodiment shows the bearing housing102 not in a supporting relationship with the rotor shaft 86.Consequently, the shaft ring 210 of the motor frame assembly 52 is in asupporting relationship with the rotor shaft 86. As the bearing housing102 moves axially inward relative to the drive shaft 110 end, slidingcontact between the tapered section 246 and the support face 204 movesthe bearing housing 102 radially inward relative to the centralrotational axis 106, thereby facilitating smooth entry of the bearinghousing 102 into the central housing bore 208. More importantly, as thebearing housing 102 moves axially and radially into the supportingrelationship, the bearing housing 102 correspondingly lifts the rotorshaft 86, such that the rotor axis 180 returns to the central rotationalaxis 106. The bearing housing 102 lifts the rotor shaft 86 off of theshaft ring 210, thereby assuming the supporting relationship, as bestillustrated in FIG. 25.

Referring now to FIG. 26, the bearing assembly 202 is in a supportingrelationship with the rotor shaft 86. The fasteners 236 securely attachthe bearing housing 102 to the motor housing 56. The alignment studs 242are removed from the fastener-receiving holes 238, and fasteners 240(e.g., socket head cap screws) are passed through the same holes 238 tosecure the inner bearing cap 220 to the bearing housing 102. The bearinghousing 102 also includes a plurality of externally-facingfastener-receiving bores 248 for the securement of a removable bearingcover plate 250 axially adjacent the bearing 166 and coaxial the rotorshaft 86. The bearing cover plate 250 includes a plurality offastener-receiving holes 252 that correspond to the bores 248 of thebearing housing. Fasteners 254 (e.g., bolts) pass through respectivecover plate holes 252 and are connected to the bearing housing 102. Thebearing cover plate 250 provides outer axial support to the bearing 166when the bearing 166 is housed within the bearing housing 102. Asillustrated, the bearing cover plate 250 can be removed to providedirect access to the bearing 166 when the bearing housing 102 is insupporting relationship with the bearing 166 and rotor shaft 86.

Disassembly of the bearing assembly 202 can be performed by reversingthe order of the above discussed steps. More specifically, some of thefasteners 236 that secure the bearing housing 102 to the motor frameassembly 52 can be completely removed, while the remaining fasteners 236are disengaged from the motor frame assembly 52 but remain in an engagedrelationship with the bearing housing 102. The engaged fasteners 236 canbe used to pry the housing 102 away from the motor frame assembly 52.After removal of the bearing housing 102, the bearing 166 cansubsequently be removed. Any suitable means for removing the bearing 166and other components mounted on the rotor shaft 86 (e.g., the bearingspacer 216 or inner bearing cap 220) can be used. An example of such isdisclosed in U.S. Provisional Patent Application Ser. No. 61/937,229entitled SYSTEMS, APPARATUSES AND METHODS FOR LIFTING, POSITIONING ANDREMOVING A BEARING ASSEMBLY FROM A SHAFT, which is hereby incorporatedby reference in its entirety herein, to the extent not inconsistent withthe present disclosure.

Also seen in the illustrated embodiment, the bearing assembly 202includes a lubricant fill channel 256 and a lubricant drain channel 258.The lubricant fill channel 256 provides an access point for applyinglubricant to the bearing 166 while the bearing housing 102 is insupporting relationship with the bearing 166 and the rotor 64. In theassembled state, the lubricant fill channel 256 leads to a feed channel260 within the inner bearing cap 220, thereby channeling lubricant intothe rollers of the bearing 166. As lubrication is dispersed, thelubricant drainage follows the feed channels 260 to the opposite side ofthe inner bearing cap 220 and drains out of the lubricant drain channel258 of the bearing housing 102.

Adjustable Rotor Sensor Carrier

In the illustrated embodiments, the motor assembly 42 includes a rotorsensor mechanism 262 for broadly sensing at least one condition of therotor. As can be appreciated by one of ordinary skill in the art,maintenance and calibration for a motor assembly of this sizenecessitates minimal displacement of major components (i.e., the rotor).Turning now to FIG. 27, removal of at least one of the access plates 80presents a window 192 that provides access to a rotor sensor mechanism262 disposed in the motor chamber 66. The rotor sensor mechanism 262broadly includes a target component 264 fixed relative to the rotor 64that rotates therewith, a sensor 266 configured to sense the targetcomponent 264, and an adjustable sensor carrier 268 that adjustablyattaches the sensor 266 to the closed end bracket 78, thus adjustablycoupling the sensor 266 to the motor frame assembly 52. The sensormechanism 262 can further include a processor 270, such that the sensor266 and processor 270 are in communication for calculating variouscharacteristics of the rotor 64.

In the illustrated embodiment of FIG. 28, the target component 264 is inthe form of a shutter wheel 272 fixed to the rotor 64. The shutter wheel272 is preferably formed of ferrous material, although other suitableconfigurations may be used (e.g., a composite wheel with ferrous teeth,etc.) The shutter wheel 272 includes an inner engagement surface 274having a keyway 276. The rotor shaft 86 includes an outer supportsurface 278 having a key 280 that corresponds with the shutter wheelkeyway 276. The shutter wheel 272 is slidably received on the rotorshaft 86, such that a marriage between the key 280 and keyway 276prevents relative rotation of the shutter wheel 272 to the rotor 64. Theshutter wheel 272 includes a fastener assembly 282 that securelyattaches the shutter wheel 272 to the rotor shaft 86. As can beappreciated by one of ordinary skill in the art, fastener assemblies forfixing various components to a rotor shaft are well known and will notbe discussed any further. The shutter wheel 272 is axially interposedbetween the motor frame assembly 52 and the rotor 64. In the illustratedembodiment, the sensor mechanism 262 is attached to the axiallyinward-facing surface of the closed end bracket 78, although othercouplings to the motor frame assembly 52 are considered.

The shutter wheel 272 includes a plurality of circumferentially spacedtarget teeth 284, 286. The illustrated embodiment includes a set ofradially projecting radial target teeth 284 and a set of axiallyextending axial target teeth 286, as more clearly illustrated in FIG.29. As will be readily appreciated by one of ordinary skill in the art,the principles of the present invention are not limited to the use ofboth radial target teeth 284 and axial target teeth 286, as they may beused interchangeably, in combination with one another, or replaced by acompletely different configuration while remaining within the scope ofsome aspects of the invention.

As shown in FIGS. 30 and 31, the sensor carrier 268 includes a sensorcarrier bracket 290 adjustably attached to the closed end bracket 78 ofthe motor frame assembly 52. In the illustrated embodiment, the sensorcarrier bracket 290 presents a pair of slotted openings 292 andfasteners 294 (e.g., bolts), with each fastener 294 passing throughopenings 292 to adjustably receive the sensor carrier 268 to the closedend bracket 78. More particularly, as best shown in FIG. 31, the slottedopenings 292 each preferably extend primarily circumferentially topresent an oval shape, thereby enabling circumferential shifting of thesensor carrier bracket relative to the motor frame assembly 52. Thebracket 290 preferably comprises a mounting tab 296, in which theslotted openings 292 are defined, and a generally L-shaped sensorsupport 298 having one or more sensors 266 mounted thereon. The sensorsupport 298 includes a generally axially extending leg 299 and agenerally radially projecting leg 300.

In the illustrated embodiment, three digital vane (axial) sensors 301are fixed to the generally radially projecting leg 300, to projectgenerally axially toward the axial target teeth 286 of the shutter wheel272. The axial sensors 301 are preferably at least generally radiallyaligned with the axial target teeth 286 and face axially toward theaxial target teeth 286. Three magnetic radial sensors 302 are fixed tothe generally axially extending leg 299, to project generally radiallytoward the radial target teeth 284 of the shutter wheel 272. The radialsensors 302 are preferably at least generally axially aligned with theradial target teeth 284 and face radially toward the radial target teeth284. In the preferred embodiment, the magnetic radial sensors 302 arespaced radially outwardly from the shutter wheel 272, such that theradial sensors 302 face radially inwardly toward the radial target teeth284. The digital vane (axial) sensors 301 are adjustably positionedrelative to the shutter wheel 272 to sense the axial target 286 teeth,while the magnetic radial sensors 302 are adjustably positioned relativeto the shutter wheel 272 to sense the radial target teeth 284.

Each sensor 266,301,302 is preferably a Hall effect sensor, capable ofsensing the relative position of a ferrous target as it passes thesensor 266,301,302. The sensors 266,301,302 are operably connected tothe processor 270. A plurality of sensors 266,301,302, working inparallel with one another, can provide the processor 270 with theappropriate data for calculating the position, speed, and direction ofrotation of the rotor 64 based upon movement of the target teeth 284,286relative to the sensors 266. Although the illustrated embodimentsgenerally include magnetic proximity sensors for detecting relativeposition of the sensors 266,301,302 with a ferrous target component 264,various sensor technologies and target components can be considered foruse within the scope of this invention. For example, the sensormechanism may alternatively use a printed marking on the rotor shaft (ora target otherwise applied to the rotor shaft) and an optical sensoradjustably supported by the carrier. It is also within the scope of thepresent invention to have a various number of sensors, as one ofordinary skill in the art would appreciate.

With attention now to FIGS. 32 and 33, the target component 264,272 isfixed relative the rotor 64. As a result, any calibrations of the sensormechanism 262 can be performed on the sensor carrier 268. The slottedopenings 292 of the sensor carrier bracket 290 allow for adjustablepositioning of the sensor carrier 268, and thereby the sensors 266,relative the target component 264,272. Thus, as sensing is processed anda precalibrated position is determined, the sensor carrier bracket 290may then be fixedly secured to the closed end bracket 78. To facilitatereturn to the precalibrated position, the sensor carrier bracket 290also presents an unslotted opening 304 and a fastener 306 for theopening (e.g., a set screw) to repeatedly fix the sensor carrier 268into the precalibrated position. In the illustrated embodiment, upondetermination of the precalibrated position, a small reference divot 308is drilled into the mounting surface 310 of the closed end bracket 78 indirect alignment with the unslotted opening 304 of the fixedly securedsensor carrier bracket 290. Thereupon, a fastener 306 (e.g., set screw)is passed through the unslotted opening 304 and secured to the closedend bracket reference divot 308.

The preferred forms of the invention described above are to be used asillustration only and should not be utilized in a limiting sense ininterpreting the scope of the present invention. Obvious modificationsto the exemplary embodiments, as hereinabove set forth, could be readilymade by those skilled in the art without departing from the spirit ofthe present invention.

The inventors hereby state their intent to rely on the Doctrine ofEquivalents to determine and assess the reasonably fair scope of thepresent invention as pertains to any apparatus not materially departingfrom but outside the literal scope of the invention set forth in thefollowing claims.

What is claimed is:
 1. An electric motor comprising: a motor frameassembly including a motor frame and a motor housing; a rotor rotatablerelative to the motor frame assembly about an axis, said rotor includinga rotor shaft rotatably supported on the motor frame assembly, saidrotor shaft presenting opposite axial ends; a stator fixed relative tothe motor frame assembly; a rotor jack operable to selectively supportthe rotor shaft, said rotor jack being shiftably coupled relative to themotor frame assembly for movement between a support position, in whichthe jack is shifted into supporting contact with the rotor shaft, and aretracted position, in which the jack is spaced from the rotor shaft;and a bearing rotatably supporting the rotor shaft on the motor frameassembly, said rotor jack being configured to support the weight andposition of the rotor when the bearing is removed, said rotor jack beingspaced axially inward relative to the bearing, said motor frame assemblypresenting a window providing access to the jack.
 2. The electric motoras claimed in claim 1, said rotor jack including a plurality of jackingcomponents shiftable between the supporting and retracted positions. 3.The electric motor as claimed in claim 2, said jacking components beingindividually shiftable between the supporting and retracted positions.4. The electric motor as claimed in claim 2, said jacking componentseach including a threaded shaft such that rotation of the shaft causesshifting of the respective jacking component between the supporting andretracted positions.
 5. The electric motor as claimed in claim 2, saidjacking components projecting radially relative to the shaft, saidjacking components being angularly spaced apart.
 6. The electric motoras claimed in claim 5, said jacking components defining an angle ofabout thirty degrees to about ninety degrees therebetween.
 7. Theelectric motor as claimed in claim 6, said angle being about fortydegrees.
 8. The electric motor as claimed in claim 2, said jackingcomponents each having a tip formed of low-friction material relative tothe rotor shaft.
 9. The electric motor as claimed in claim 8, saidlow-friction material comprising nylon.
 10. The electric motor asclaimed in claim 1, said rotor weighing at least about ten thousandpounds.
 11. A method of replacing a rotor shaft bearing of a motor, saidbearing replacement method comprising the steps of: (a) shifting a jackinto supporting contact with the rotor shaft so that the jack supportsthe weight and position of the rotor; (b) removing an existing bearing;(c) installing a new bearing; (d) retracting the jack from supportingcontact with the rotor shaft so that the new bearing supports the weightand position of the rotor; (e) removing a cover plate from a motor frameassembly on which the rotor is rotatably supported; and accessing thejack through a window defined in the motor frame assembly.
 12. Thebearing replacement method of claim 11; and (g) prior to step (a),stopping the rotor shaft.
 13. The bearing replacement method of claim11, step (a) including the step of threading a jacking componentrelative to a motor frame assembly into supporting contact with therotor shaft, step (b) including the step of threading a jackingcomponent relative to the motor frame assembly out of supporting contactwith the rotor shaft.
 14. The bearing replacement method of claim 11,step (a) including the steps of shifting multiple jacking componentsrelative to a motor frame assembly into supporting contact with therotor shaft, step (b) including the steps of shifting multiple jackingcomponents relative to the motor frame assembly out of supportingcontact with the rotor shaft.
 15. The bearing replacement method ofclaim 11, during step (a), sensing shaft movement to determine when thejack has been shifted into supporting contact with the rotor shaft. 16.The bearing replacement method of claim 11, step (a) including the stepof threading a jacking component relative to a motor frame assembly intosupporting contact with the rotor shaft, step (b) including the step ofthreading a jacking component relative to the motor frame assembly outof supporting contact with the rotor shaft.